A lot of people copmplained about the career game several times, that once you've maxed out the tech tree, the game is over. In every game with a tech tree \ {KSP} at the very end of the tech tree there is a tech that's generally called 'future tech', that can be researched many times, and it gives you money (or other valuable in-game rescoures). There should be one in KSP, researching wich would requie you to research all previous techs, and it would give much more money or reputation than what strategies currently give.